1. Field of the Invention
The invention pertains generally to the winding of a filament onto a bobbin or canister for use as a data link, and, more particularly, for apparatus to secure the last several windings on an end portion of a canister attendant the beginning of an upper winding layer.
2. Description of the Prior Art
Many present day missile weapons include an extended length of a filament such as a wire or optical fiber wound onto a canister, one end of which is connected to apparatus aboard the missile and the other end being connected to apparatus at the launch site. On launch, the filament unwinds maintaining via the data link as a communications line for controlling the missile. Since an optical fiber is a preferred form of filament for this purpose, it will be used hereafter.
In winding the optical fiber onto the canister, it is important not to stretch or kink the fiber since this can substantially deteriorate the quality of a light signal being transmitted. One particular difficulty encountered in the winding of an optical fiber is that on moving from the end of one winding layer to the beginning of the next, the fiber is twisted out of the plane of the lower winding layer as well as being raised radially upwardly producing a "micro bend" which must be kept as small as possible to prevent the deterioration of the signal transmission already noted.
In certain other situations, the layers are applied onto a tapered canister so that an upper layer may start a number of turns back from the end of the underlying layer which complicates the winding procedure and the prevention of bending, stressing or micro bending during the winding.
Irrespective of the canister form it is necessary to set a specific transition point between layers during a fiber spooling operation. In the past, this has only been successfully accomplished manually where the operator had to set each layer end transition by hand. Of course, this is a very difficult and unreliable way of setting a layer end transition and it is desirable to be able to accomplish this by a machine control technique.